Drp1 Is Dispensable for Mitochondria Biogenesis in Induction to Pluripotency but Required for Differentiation of Embryonic Stem Cells

Abstract

Mature mitochondria with high oxidative phosphorylation undergo fission and fusion and morphogenesis to become immature mitochondria during induced pluripotent stem (iPS) induction from somatic cells. Dynamin-related protein 1 (Drp1) is involved in mitochondria fission and biogenesis in somatic cells. We tested the role of Drp1 in the induction and maintenance of pluripotency. We show that Drp1 band shift occurs in embryonic stem cells (ESCs) and iPS cells (iPSCs) induced from fibroblasts, in association with mitochondrial morphogenesis. However, knockdown of Drp1 by shRNA does not abrogate mitochondria morphogenesis and induction of iPSCs from fibroblasts. Also, knockdown of Drp1 affects neither mitochondria fission and function as shown by normal mitochondrial membrane potential, nor proliferation and pluripotency of ESCs. Nonetheless, Drp1 knockdown negatively influences terminal differentiation of ESCs, particularly in the lineage of neurogenesis in vitro and in vivo, coincident with delayed reduction of Oct4 and Nanog during mid-differentiation. Our data suggest that Drp1 is not critical for mitochondria biogenesis in stem cell proliferation but it is required for neurogenesis likely by downregulation of pluripotency-associated genes Nanog and Oct4. ESC differentiation model could be used to model role of Drp1 in neuron development and diseases.

MtDNA depleted PC3 cells exhibit Warburg effect and cancer stem cell features

“…But, recently L Wang et, al. also demonstrated that although mito-fission related gene Dnm1l (Drp1) was upregulated during inducing pluripotent cells, knocking down Drp1 did not affect inducing pluripotent result [58]. We have observed that the mitochondrial dynamic alternations and the immature mitochondrial morphology support our hypothesis that mtDNA depletion tumor cells survive through metabolic reprogramming towards aerobic glycolysis with Warburg effect (see also Supplementary Figure S1B and S1C), hence, the survived cells may hold greater cell stemness.…”

Connecting Mitochondria, Metabolism, and Stem Cell Fate

“…Although mainly considered as a component of the mitochondrial fission machinery, DRP1 can also promote mitochondrial fusion by its interaction with MFN2 [60]. The knockdown of DRP1 leads to the elongation of the mitochondrial network of fibroblasts, but it does not cause substantial changes in the morphology of mouse ESC/iPSC mitochondria [58]. These findings suggest that the discrepancies between the previous studies might also depend on DRP1 playing a different role in mitochondrial dynamics in different cells.…”

“…Although these data suggest a critical role for DRP1-mediated mitochondrial fission in the pluripotency of hESCs, studies of mESCs reported contradictory results. In mouse embryonic fibroblasts, although pharmacological inhibition of the self-assembly of DRP1 reduces the reprogramming efficiency [57], the knockdown of DRP1 expression does not affect pluripotency gene expression [58]. In addition, the increased levels of DRP1 resulting from the depletion of growth factor erv1-like, a flavin adenine dinucleotide-dependent sulfhydryl oxidase predominantly found in the intermembrane space of mitochondria, inhibit the expression of pluripotency markers in mESCs [59].…”

“…Furthermore, tight control of DRP1 levels and/or activity, possibly regulated by different post-translational modifications, might underlie these observations. Beyond its involvement in pluripotency, DRP1-mediated fission is required for the terminal differentiation of mESCs in neuronal lineages [58] as well as for the myogenic differentiation of myoblasts [61].…”

Mitophagy-driven mitochondrial rejuvenation regulates stem cell fate

“…Because the unique metabolic state required to achieve cell plasticity is accompanied by significant temporal changes in mitochondrial function, composition, structure, and maturation, it might appear elementary to suggest that mitophagy is a prerequisite of induced pluripotency. Nonetheless, recent studies have shed light on how interlinked processes critical for mitochondrial health, including mitochondrial fragmentation and mito-chondrial fission/fusion, significantly alter the efficiency and speed of induced pluripotency [48-51], but little information is available on the role of mitophagy in the acquisition and maintenance of stemness.…”